1. Field of the Invention
The present invention relates to systems and methods for examining biological material. In particular, the invention relates to improved optical readers or scanners for detecting emissions from biological probe arrays having small features that may be arranged in high densities on the arrays.
2. Related Art
Synthesized nucleic acid probe arrays, such as Affymetrix GeneChip® probe arrays, and spotted probe arrays, have been used to generate unprecedented amounts of information about biological systems. For example, the GeneChip® Human Genome U133 Set (HG-U133A and HG-U133B) available from Affymetrix, Inc. of Santa Clara, Calif., is comprised of two microarrays containing over 1,000,000 unique oligonucleotide features covering more than 39,000 transcript variants that represent more than 33,000 human genes. Analysis of expression data from such microarrays may lead to the development of new drugs and new diagnostic tools.